1. Receptors Functions and Signal Transduction L1
Faisal I. Mohammed, MD, PhD
University of Jordan

2. Introduction to Physiology (0501110) Spring 2014
Subject
Lecture No.
Lecturer
Pages in the 12th edition textbook
Receptors: types and adaptation
- Membrane or intracellular
- Ion channels
- G-protein
- Enzyme linked
- Intracellular
- Second messengers
- cAMP and cGMP, Phospholipid
- Calcium calmodulin and IRS
1-2
Dr. Faisal
Signal Transduction (Regulation of cellular machinery)
Extracellular regulators: nervous, endocrine, paracrine and autocrine
3-4
Steroids: Their Signal Transduction And Mechanism Of Action 5
931
Textbook: Guyton Medical Textbook of Physiology By: Guyton and Hall 12th edition

3. Objectives Define first messenger (Hormones) List hormone types
Describe receptor types
Outline the hormone receptors interactions
Describe second messenger mechanism of action
List second messengers
University of Jordan

4. University of Jordan

5. University of Jordan

6. University of Jordan

7. Intercellular Communication
Endocrine
Target Cell
Blood
Hormone
Hormone
Neuroendocrine
Neuron
Target Cell
Blood
Hormone
Hormone
Paracrine
Cell
Interstitial Fluid
Target Cell
Hormone
Hormone
Autocrine
Cell
Interstitial Fluid
Hormone

8. University of Jordan

9. GAS MOLECULE
University of Jordan

10. University of Jordan

11. University of Jordan

12. University of Jordan

13. Endocrine Glands and Hormones
Neurohormone:
Specialized neurons that secrete chemicals into the blood rather than synaptic cleft.
Chemical secreted is called neurohormone.
Hormones:
Affect metabolism of target organs.
Help regulate total body metabolism, growth, and reproduction.
University of Jordan

14. Classes of Hormones Peptide and Protein Hormones (amino acid chain)
Steroid Hormones (derived from chlesterol)
Amine Hormones (derived from amino acid e.g tyrosin)
Gas – Nitric Oxide (NO)
University of Jordan

15. Paracrine – act on neighboring cells
Hormone types
Circulating – circulate in blood throughout body
Local hormones – act locally
Paracrine – act on neighboring cells
Autocrine – act on the same cell that secreted them
University of Jordan

16. University of Jordan

17. Chemical classes of hormones
Lipid-soluble hormones- use transport proteins in the plasma
Steroid: Lipids derived from cholesterol.
Are lipophilic hormones.
Testosterone.
Estradiol.
Cortisol.
Progesterone.
Thyroid ( amine but lipid soluble)
Nitric oxide (NO)
University of Jordan

18. Chemical classes of hormones …cont
Water-soluble – circulate in “free” form in the plasma
Amines:
Hormones derived from tyrosine and tryptophan.
Polypeptides and proteins:
Polypeptides:
Chains of < 100 amino acids in length.
ADH.
Protein hormones:
Polypeptide chains with > 100 amino acids.
Growth hormone.
Eicosanoid (prostaglandins) derived from arachidonic acid (20 carbon 4 double bonds)
University of Jordan

19. Chemical Classification of Hormones …cont
Glycoproteins:
Long polypeptides (>100) bound to 1 or more carbohydrate (CHO) groups.
FSH and LH, TSH and hCG (human chorionic gonadotropin)
They have α and β subunits (α is common and β is specific)
Hormones can also be divided into:
Polar:
H20 soluble.
Nonpolar (lipophilic):
H20 insoluble.
Can gain entry into target cells.
Steroid hormones and T4 (thyroxine –tetraiodothyronine))
University of Jordan

20. Prohormones and Prehormones
Precursor is a longer chained polypeptide that is cut and spliced together to make the hormone.
Proinsulin – gives insulin
Preprohormone:
Prohormone derived from larger precursor molecule.
Preproinsulin.
Prehormone:
Molecules secreted by endocrine glands that are inactive until changed into hormones by target cells.
T4 converted to T3 (tri-iodothyronin).
University of Jordan

21. Peptide & Protein Hormones
Gland/Tissue
Hormones
Gland/Tissue
Hormones
Hypothalamus
Anterior pituitary
Posterior pituitary
Thyroid
Pancreas
Liver
Parathyroid
TRH, GnRH, CRH
GHRH, Somatostatin,
ACTH, TSH, FSH, LH,
PRL, GH
Oxytocin, ADH
Calcitonin
Insulin,Glucagon,
Somatostatin
Somatomedin C (IGF-1)
PTH
Placenta
Kidney
Heart
G.I. tract
Adipocyte
Adrenal medulla
HCG, HCS or HPL
Renin
ANP
Gastrin, CCK,
Secretin, GIP,
Leptin
Norepinephrine, epinephrine
University of Jordan

22. Synthesis and secretion of peptide hormones
University of Jordan

23. Amine Hormones Gland/Tissue Hormones Hypothalamus Thyroid
Adrenal medulla
Dopamine
T3, T4
Epinephrine and Norepinephrine (NE, EPI)
University of Jordan

24. Synthesis of Amine Hormones
Tyrosine
tyrosine hydroxylase
L-Dopa
dopa decarboxylase
Dopaminergic Neurons
Dopamine
dopamine  -hydroxylase
Adrenergic Neurons
Norepinephrine
phenylethanolamine-N-methyltransferase
Thyroid Hormones
Epinephrine
Thyroid Gland
Adrenal Glands

25. Steroid Hormones Adrenal Cortex Testes Ovaries Corpus Luteum Placenta
Gland/Tissue
Adrenal Cortex
Testes
Ovaries
Corpus Luteum
Placenta
Kidney
Cortisol, Aldosterone, Androgens
Testosterone
Estrogens, Progesterone
1,25-Dihydroxycholecalciferol
(calcitriol)
University of Jordan

26. Thank you